JP2006274917A - Manufacturing method for hollow poppet valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a biggest problem of speeding-up of welding work, in a step closing a lightening hole of a hollow poppet valve with a cover member, and a problem that a welded part area cannot be kept smoothly and compact although a resistance melding is preferable to speed up the work. <P>SOLUTION: A semi-formed poppet valve molded in a hollow shape by the lightening hole, and the cover member closing the lightening hole are prepared. A pad part is formed by a resistance welder. The resistance welder has: a receiving shape electrode supporting the semi-formed poppet valve with its flare part side up; and a pressing shape electrode supporting a lower face of the circular cover member closing the lightening hole, and the resistance welder pushes the cover member against the semi-formed poppet valve and applies current between the pushing shape electrode and receiving shape electrode to weld them. The pad part is projected from a peripheral part of the circular core member in a pushing shape electrode direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a hollow poppet valve in which a stem and a flare are formed from a steel plate integrally formed with a hollow hole having an axial hollow hole, and in particular, a lid member for closing the hollow hole. It relates to a fixing method.

In general, the poppet valve is commonly used as an intake / exhaust valve of an engine. In order to reduce the weight and prevent knocking in a high-performance engine, as shown in FIG. The so-called hollow poppet valve 80 is well known, which is made by sealing with a lid member 86, enclosing sodium inside, and welding so that the lid member 86 does not come off.
. However, if the welding mark that closes the lid member is not smooth, it becomes a hot spot, and knocking is likely to occur. Conventionally, it is smoothed by finishing after welding.

  In recent years, many high-performance engines have been demanded in the market, and light hollow poppet valves have been demanded in many ways to reduce fuel consumption. There is a strong demand for efficient production.

  In order to efficiently perform the welding operation for closing the lid member, it is preferable to perform electrical resistance welding, particularly projection welding, instead of arc welding performed in an inert gas atmosphere such as conventional TIG or MIG. Projection welding is preferable to reduce welding marks, but if the amount of material melted is not stable, the height of the lid member will fluctuate, the compression ratio will not easily vary, and the molten material will easily adhere to the surroundings. There was a problem that required post-processing to remove it.

As a measure to improve this, there is a method in which a valve plate having a conical valve surface at the periphery is used as a lid member for closing the lightening hole, and a stem is welded to the back surface thereof.
. However, since the valve plate is directly subjected to the combustion pressure, the plate thickness must be increased, and even if the corner and the poppet valve are hollow, the effect of weight reduction is greatly diminished. FIG. 3 in Japanese Patent Laid-Open No. 2003-65013 JP 2001-221348 A

  The problem to be solved by the present invention is that the amount of melting of the lid member itself is reduced as much as possible when the lid member is welded to the semi-finished product of the hollow poppet valve provided with the hollow hole by the electric resistance welding method. Such a configuration is required.

  The present invention provides a poppet valve semi-finished product that is hollowly formed by a lightening hole provided from a stem to a flare portion, and a lid member that closes the lightening hole, and supports the flared portion of the poppet valve semi-finished product upward. And a push-type electrode that supports the circular lid member that closes the lightening hole on the lower surface, and presses the lid member against the poppet valve semi-finished product to energize between the push-type electrode and the receiver electrode. They are joined by a resistance welding machine. In addition, the most important feature is to form a surplus portion protruding in the direction of the push electrode at the peripheral edge of the circular lid member.

  According to the method for manufacturing a hollow poppet valve according to the present invention, the opening of the lightening hole can be closed by an electric resistance welding method, and high productivity can be achieved in mass production of the hollow poppet valve. In addition, since the boundary portion between the inner surface of the flared portion subjected to resistance welding and the welded portion between the peripheral portion of the lid member forms a smooth surface, the finishing process can be omitted or minimized.

  FIG. 1 is a sectional view showing an embodiment of a welding apparatus embodying the method of the present invention. The welding device 10 is disposed above the receiving electrode 20 fixed to the upper surface of the welding table 12, and can be lowered toward the receiving electrode 20 or can be raised from the lowered position. And a configured push-type electrode 30.

  Reference numeral 14 denotes a power supply device for supplying power to both electrodes 20 and 30. In addition, since the means for raising / lowering the push electrode 30 is well known in the art, illustration is omitted.

  Reference numeral 40 denotes a hollow poppet valve that is a workpiece. The hollow poppet valve includes a semi-finished hollow poppet valve that has been completed up to a pre-process for welding a lid member 45 described later. The hollow poppet valve semi-finished product 40 is obtained by ironing a steel material. The hollow poppet valve 40 has an outer surface in which a stem 41 and a valve portion 42 are smoothly connected by a flare portion 43, and a meat hole punched in the stem 41 is provided. The wall thickness is smoothly increased from the hole 44 through the flare portion 43 to the valve portion 42. By changing the wall thickness in this manner, a hollow poppet valve that can withstand strong combustion pressure and is lightweight can be obtained.

  As apparent from FIG. 7A, the lid member 45 includes a central portion 45a obtained by curving a relatively thin steel plate in a hemispherical shape and trimming the outer periphery into a circular shape, and a peripheral portion of the central portion 45a as a recurved portion 45b. Is bent in the opposite direction (upward in the drawing), and the flange portion on the outer peripheral side from the bent portion 45b is used as the surplus portion 45c. The shape of the lid member 45 is not limited to this, and depending on the combustion chamber, the central portion 45a can be flattened as necessary, or can be recessed to the opposite side as shown in FIG. It is.

  When the lid member 45 having such a shape is attached to the welding apparatus 10, the lid member 45 abuts on the push-shaped electrode 30 at the periphery of the surplus portion 45c, and abuts on the flare portion at the portion of the recurved portion 45b. The annular receiving electrode 20 and the pressing electrode 30 are arranged at the shortest distance so that the welding current is concentrated between the electrodes 20 and 30 to reduce wasteful power consumption.

  The receiving electrode 20 of the welding apparatus 10 has a cylindrical body made of a copper alloy, and its axial center is coaxially attached to a circular relief hole 12 a provided in the welding table 12. 20a is a guide for guiding the stem 41 provided at the lower part of the cylindrical body, and is composed of several plate-like members extending from the inner surface of the cylindrical body in the axial direction. The upper surface of the receiving electrode 20 is formed in a bowl shape with a lowered central portion, and the angle of contact with the flare portion 43 of the hollow poppet valve 40 becomes an obtuse angle to reduce wear, and the hollow poppet valve 40 is supported. Become stable.

  The push-type electrode 30 has a cylindrical body made of a copper alloy, and an insulating guide ring 34 urged downward by a spring 32 is slidably fitted to the outer periphery of the lower end portion thereof. Further, a permanent magnet 36 as a holding means for the lid member 45 is held at the central lower end. Reference numeral 38 denotes a relief hole opened at the lower end of the push-type electrode 30. Since the push electrode 30 is configured as described above, the lid member 45 can be attracted to the lower end portion by the attractive force of the permanent magnet 36. Note that the holding means is not limited to a magnetic force, and aerodynamic means such as a vacuum can be used in the case of a material that hardly reacts to the magnet, such as stainless steel or titanium.

  Next, the operation of the welding apparatus 10 will be described. First, the prepared poppet valve semi-finished product 40 and the lid member 45 are set to the welding apparatus 10 in the state shown in FIG. That is, the poppet valve semi-finished product 40 is supported on the receiving electrode 20 with the flare portion 43 facing upward. Next, the surplus portion 45 c of the lid member 45 is brought into contact with the lower surface of the push-type electrode 30, positioned by the guide ring 34, and attracted and held by the permanent magnet 36.

  When ready, when the push-type electrode 30 is lowered while energizing between the electrodes 20 and 30, the guide ring 34 first comes into contact with the poppet valve semi-finished product 40 and further progress is prevented. When the shape electrode 30 is lowered as it is, the guide ring 34 is moved upward while compressing the spring 32, and the push electrode 30 is lowered to the position shown in FIG. These operations are performed instantaneously as is well known in practice.

  In this state, both the electrodes 20 and 30 are short-circuited via the surplus portion 45c, a large current flows and the surplus portion 45c softens instantaneously, and the pressing force of the push-type electrode 30 causes a reduction in FIG. As shown in FIG. 3, the deformation is shown to be caused to enter the wedge-shaped gap c between the lower surface of the push-type electrode 30 and the inner surface of the lightening hole 44 corresponding to the inside of the flare portion 43.

  At the same time, the inner surface of the lightening hole 44 is also melted, and as shown by the symbol d in FIG. In this state, the surplus portion 45c is once melted to fill the gap c. Therefore, as shown in FIG. 6, there is a smooth smooth portion p between the inner side of the flare portion 43 and the lid member 45 with little unevenness. Is obtained.

It is sectional drawing of the principal part of the welding apparatus which concerns on this invention. It is sectional drawing of the principal part which shows the preparation process of a welding process. It is sectional drawing of the principal part which shows the initial stage process of a welding process. It is sectional drawing of the principal part which shows the intermediate | middle process of a welding process. It is sectional drawing of the principal part which shows the final process of a welding process. It is sectional drawing of the principal part which shows the taking-out process of a welding process. (A) is sectional drawing which expands and shows a cover member, (b) is sectional drawing which shows another Example. It is a half section front view of the conventional hollow poppet valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Welding device 12 Welding table 12a Relief hole 14 Power supply device 20 Receiving electrode 20a Guide 30 Pushing electrode 32 Spring 34 Guide ring 36 Permanent magnet 38 Relief hole 40 Workpiece (half-finished product of hollow poppet valve)
41 Stem 42 Valve 43 Flare 44 Flare Hole 45 Lid Member 45a Center 45b Recursion 45c Extra Material 80 Hollow Poppet Valve 82 Stem 84 Flare Hole 86 Lid Member c Clearance d Diffusion Part p Smoothing Part

Claims (4)

  A receiving electrode that supports a poppet valve semi-finished product hollowly formed by a lightening hole provided from a stem to a flare part and a lid member that closes the lightening hole and supports the flare part of the poppet semi-finished product facing upward And a push-type electrode that supports the circular lid member that closes the lightening hole on the lower surface, and presses the lid member against the semi-finished poppet valve to energize and weld between the push-type electrode and the receiving electrode. Method of manufacturing a hollow poppet valve connected by a machine.   2. The method of manufacturing a hollow poppet valve according to claim 1, wherein the circular lid member is formed with a surplus portion protruding in the direction of the push electrode at the peripheral edge.   In claim 1, the lid member is made of a plate material formed in a circular shape, the surplus portion protruded in the direction of the push electrode at the peripheral edge portion, the peripheral edge portion of the plate member is once bent toward the inner surface of the flare portion, Next, a method of manufacturing a hollow poppet valve formed by folding back in the opposite direction.   2. The method of manufacturing a hollow poppet valve according to claim 1, wherein the push-type electrode is provided with holding means for temporarily holding the lid member.

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